Heretofore, some compounds such as anthracycline have been reported as antibiotics having anthraquinone skeleton CRC Handbook of Antibiotic Compounds, 3, 61 (1981)!.
Further, UCT 1003 (Saintopin) having anti-tumor activity which is represented by the following formula A: ##STR2## has also been known Biochemistry, 30, 5838-5845 (1991); Japanese Published Unexamined Patent Application No. 200655/90!.